I have an standard Android app A and a second Android app B which has a shared library (.so/NDK).
I want to setup a secure communication protocol between the two of them. I thought about using a simple localhost socket and use mTLS certificates to secure the channel.
Is there a way to store certificates safely in the Android system so that nobody else can read it? I’ve read about key-attestation but do not have experience with that.

Would there be an alternative to communicate between a standard Android App and a NDK/.so library? I tried to used AIDL, could also generate the headers. But it appears as if NDK is lacking the libraries for setting up the bound service (only AOSP has the libraries). So I was not able to set up a bound service client with only using NDK.